Run LanguageTool locally on macOS

Grammarly like tool but without sending all of my keystrokes to the cloud. The Safari extension enables grammar checks on all text inputs.

To make it work it needs multiple components installed locally:

languagetool itself
fasttext for language detection
fasttext model for language detection

Installation

brew install languagetool

To test it out run the following commands. The curl command should show JSON output.

languagetool-server --port 8081 --allow-origin '*'

Open http://localhost:8081/v2/check?language=en-US&text=my+text to see if it works.

Local HTTPs

To make the local server usable in Safari, it needs to use HTTPS. We can use caddy as a reverse proxy locally. It automatically manages a locally trusted certificate.

To test if HTTPs proxying works, run the following command.

caddy reverse-proxy --from localhost:8082 --to localhost:8081

Open https://localhost:8082/v2/check?language=en-US&text=my+text to see if it works.

Fasttext

Without this tool, LanguageTool will make mistakes detecting the language and recommend changes based on another language.

mkdir /usr/local/share/fasttext

curl https://dl.fbaipublicfiles.com/fasttext/supervised-models/lid.176.bin -o /usr/local/share/fasttext/lid.176.bin

Start in background

Create the file ~/Library/LaunchAgents/org.languagetool.server.plist with this content:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <key>KeepAlive</key>
        <true />
        <key>Label</key>
        <string>org.languagetool.server</string>
        <key>ProgramArguments</key>
        <array>
            <string>/usr/local/bin/languagetool-server</string>
            <string>--port</string>
            <string>8081</string>
            <string>--allow-origin</string>
            <string>*</string>
        </array>
        <key>RunAtLoad</key>
        <true />
        <key>KeepAlive</key>
        <true />
        <key>inetdCompatibility</key>
        <dict>
            <key>Wait</key>
            <false />
        </dict>
    </dict>
</plist>

Create the file ~/Library/LaunchAgents/org.languagetool.caddy-proxy.plist with this content:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
    <dict>
        <key>KeepAlive</key>
        <true />
        <key>Label</key>
        <string>org.languagetool.caddy-proxy</string>
        <key>ProgramArguments</key>
        <array>
            <string>/usr/local/bin/caddy</string>
            <string>reverse-proxy</string>
            <string>--from</string>
            <string>localhost:8082</string>
            <string>--to</string>
            <string>localhost:8081</string>
        </array>
        <key>RunAtLoad</key>
        <true />
        <key>KeepAlive</key>
        <true />
        <key>inetdCompatibility</key>
        <dict>
            <key>Wait</key>
            <false />
        </dict>
    </dict>
</plist>

Then load both automatically at startup:

launchctl load ~/Library/LaunchAgents/org.languagetool.server.plist

launchctl load ~/Library/LaunchAgents/org.languagetool.caddy-proxy.plist

Use launchctl unload [file] to uninstall.

Safari Extension

In the LanguageTool settings, under "Experimental settings" enter https://localhost:8082/v2 as the Other server setting.

Obsidian Integration

Use Obsidian LanguageTool Plugin with the URL https://localhost:8082 to enable LanguageTool on notes.

Sources

#published

These notes are unpolished collections of thoughts, unfinished ideas, and things I want to remember later. In the spirit of learning in public, I'm sharing them here. Have fun exploring, if you want!